This bug affects me, too, on an amd64 system after an in-place do-release-upgrade upgrade from 18.04 LTS yesterday.
I have no interactions with an OpenWRT box, though.
My config is currently a WiFi connection away from home, with an automatic OpenVPN tunnel to my router at home, using split DNS to resolve a private .prv domain for my home network.
This bug affects me, too, on an amd64 system after an in-place do-release-upgrade upgrade from 18.04 LTS yesterday.
I have no interactions with an OpenWRT box, though.
My config is currently a WiFi connection away from home, with an automatic OpenVPN tunnel to my router at home, using split DNS to resolve a private .prv domain for my home network.
The problem did not exist with 18.04 LTS.